Microactuators are devices that can exert a force or execute a movement upon external stimulation. Some are made of a bi-layer of a conducting polymer and a carrier substrate of e.g. metal or a polymer. These devices can have lateral dimensions ranging from micrometers to centimeters and layer thickness in the range of nanometers to millimeters.
When such a microactuator is subjected to an electrical current this causes a relative volume change between the layers. This relative volume change between the layers will lead to a bending movement of the microactuator. Forces stemming from the material with the largest volume change being connected to a material with a smaller volume change cause the bending movement.
The function of such microactuators is disclosed for instance in E. Smela, O. Inganäs, I. Lundström “Controlled Folding of Micrometer-Size Structures”, Science, Vol. 268, p. 1735-1738.
The development of microactuators has opened up a wide variety of possible new applications, e.g. in electronics and in minimal invasive surgery.
The bending movement achieved with the above-described construction has been shown to be difficult to control. Therefore, there is a need for a construction, which gives better control of movement.